Friday, 3 October 2014

Cize–Bolozon Viaduct: A Rail-Road Crossing Bridge in France

SNCF B 81661 is passing is a spectacular scene on the Cize-Bolozon
viaduct which is a road-rail bridge crossing the Ain gorge in France. The
Cize–Bolozon viaduct is a combination of rail and vehicular viaduct crossing
the Ain gorge linking the communes of Cize and Bolozon. Therefore an original
span built in the same location in 1875 was actually ruined in World War 2. It
was reconstructed as a vital post-war plan due to its position on a main line
to Paris; however the new viaduct revived in May 1950. Interestingly The Cize
Bolozon viaduct was only opened five years after the end of the war, on 14 May
1950.

Unique engineering works on the line include the road-rail
Cize-Bolozon viaduct, carrying the railway on the high level and the road on
the low level and the overhead conductor rail used in the Bolozon I and Bolozon
II tunnels and the open track in between. It carries road and rail traffic at
diverse levels: the railway, which was barred for reinforcement and restoration
work in 2005, occupies the upper level. The vehicles which are crossing the
Cize-Bolozon viaduct, the speed falls to 80 km/h, and then picks up again to 90
through the Bolozon and Mornay tunnels.

Nevertheless the part of the Ligne du Haut-Bugey reopened in December
2010 as part of the international Paris–Geneva line. However the local road
from Poncin to Thoirette uses the lower level. Racouse tunnel takes the line
through the second ridge of the Revermont, and then the Cize-Bolozon viaduct
crosses the river Ain to Bolozon station. Numerous bridges were destroyed in
1944, starting with the bridge over the Suran on July 8, followed by the Cize
Bolozon viaduct on the 8th and the Reyssouze Bridge on 2 September.